The city's Board of Health on Thursday passed a rule banning sales of big sodas and other sugary drinks at restaurants, concession stands, and other eateries.

The regulation, which was proposed in the spring by Mayor Michael Bloomberg and approved by panel of health experts after several months of review, puts a 16-ounce size limit on cups and bottles of non-diet soda, sweetened teas, and other calorie-packed beverages. The ban is supposed to go into effect mid-March, six months after approval.

The ban will apply in fast-food joints, movie houses and Broadway theaters, workplace cafeterias, and most other places selling prepared food.

It doesn't cover beverages sold in supermarkets or most convenience stores.

The restaurant and beverage industries have assailed the plan is misguided. They say the city's health experts are exaggerating the role sugary beverages have played in making Americans fat.

"I am still skeptical. . This is not comprehensive enough," Caro said.

Some New Yorkers have also ridiculed the rule as a gross government intrusion and tens of thousands signed a petition, circulated by the industry, voicing their opposition.

The unprecedented regulation would follow other ambitious health moves on Bloomberg's watch.

The mayor and other advocates for the soda plan — who include a roster of doctors and such food figures as chef Jamie Oliver — see it as another pioneering step for public health.

They say the proposal strikes at a leading cause of obesity simply by giving people a built-in reason to stop at 16 ounces: 200 calories, if it's a regular Coke, compared to 240 in a 20-ounce size. For someone who drinks a soda a day, the difference amounts to 14,600 calories a year, or the equivalent of 70 Hershey bars, enough to add about four pounds of fat to a person's body.

Beyond the numbers, some doctors and nutrition experts say the proposal starts a conversation that could change attitudes toward overeating. While there are many factors in obesity, "ultimately it does come down to culture, and it comes down to taking some first steps," said Dr. Jeffrey Mechanick, a Mount Sinai School of Medicine professor who has studied the effect of government regulation on the obesity epidemic.

Soda makers and sellers say the plan unfairly singles out soft drinks as culprits for the nation's fat problem, represents an overweening government effort to regulate behavior and is so patchy as to be pointless. Because of the web of who regulates what, it would affect a belly-buster regular soda sold at a sports arena but not a 7-Eleven Big Gulp, for instance.

An average New Yorker goes to the movies about four times per year and buys concessions only twice, said Sun Dee Larson, a spokeswoman for the AMC Theatres chain.

"We firmly believe the choices made during the other 363 days have a much greater impact on public health," she said in a statement.

The plan is expected to be approved by the Bloomberg-appointed health board and then could take effect next March. It's unclear what the prospects are for last-minute changes before the vote. Health Commissioner Dr. Thomas Farley has noted that the board has been reviewing the public comments.

A soft-drink industry sponsored group called New Yorkers for Beverage Choices — which says it has gathered more than 250,000 signatures on petitions opposing the soda plan — is considering a lawsuit and exploring legislative options for challenging the plan if it passes, spokesman Eliot Hoff said. It's not clear what legislative routes there may be: City Council Speaker Christine Quinn said Wednesday she's not interested in trying to block the expected health board vote, though she has said she isn't a fan of the soda idea.

The rule wouldn't apply to lower-calorie drinks, such as water or diet soda, or to alcoholic beverages or drinks that are more than half milk or 70 percent juice.

Enforcement would be conducted by an existing corps of city restaurant inspectors. A violation would lead to a $200 fine.